1. Field of the Invention
The present invention relates to a lift support device, especially to a lift support device capable of increasing friction.
2. Description of Related Art
For meeting the requirement of changing viewing angles, a display, especially a flat display, is equipped with an elevation angle adjusting function, and some skilled people in the art have also developed a height adjusting function, so the height of the display is enabled to be adjusted for matching with viewers having various body shapes thereby complying the requirement of ergonomics.
Generally, the lift support device used in a display is installed with a support seat between a pair of slide rails, mobile rails installed at two sides of the support seat can be longitudinally moved along fixed rails of the slide rails, thereby adjusting the height of the display. Moreover, for providing a stopped and positioned effect to the display, skilled people in the art install at least a constant-force spring between the support seat and a vertical frame, so the elastic force provided by the constant-force spring can be used for balancing the weights of the display and the support seat and the friction of the pair of slide rails, however, the balancing means is the prior art therefore no further illustration is provided.
As such, when the elastic force provided by the constant-force spring is balanced with the weights of the display and the support seat and the friction of the pair of slide rails, the display can be adjusted to a proper height. With the dimension of the display getting larger and larger, the weight of the display is greatly increased, a constant-force spring having larger elastic coefficient has to be used for allowing the elastic force to be balanced with the mentioned gravity and friction.
If the elastic force provided by the mentioned constant-force spring is smaller than the weights of the display and the support seat and the friction of the pair of slide rails, the display would be lowered and abutted against the bottom of the pair of slide rails of the vertical frame, the height adjustment is unable to be processed. On the other hand, if the elastic force provided by the mentioned constant-force spring is greater than the weights of the display and the support seat and the friction of the pair of slide rails, the display would be lifted and abutted against the top of the pair of slide rails of the vertical frame, the height adjustment is also unable to be processed. As such, if a friction compensating mechanism is additionally installed between the support seat and the vertical frame, the insufficient elastic force or overly-large elastic force provided by the constant-force spring can be compensated, so the elastic force provided by the constant-force spring and the friction provided by the friction compensating mechanism can be balanced with the weights of the display and the support seat and the friction of the pair of slide rails, thereby facilitating the height adjustment of the display.